Gunners team-mate Matteo Guendouzi seemed visibly shaken by the incident as the medical team put an oxygen mask on Welbeck and put him on the stretcher.
Arsenal confirm that Welbeck has gone to hospital following injury suffered against Sporting. #ARSSCP— Chris Wheatley (@ChrisWheatley_) November 8, 2018
Former teammate Nani, who played with Welbeck at Manchester United, was also quick to check on the Arsenal forward on his way off the pitch.
Arsenal revealed later that the 27-year-old has been taken to hospital, and coach Unai Emery described the injury as "the worst news" of the night in a press conference.
The tributes to Welbeck had already started by then, however, as his current and former team-mates passed on their good wishes.
Having been the victim of several long-term injuries throughout his career, Cazorla shared a heart-warming for the attacker.
"Get well soon my friend," Cazorla, who left Arsenal to join Villarreal this year, posted on Instagram.
"These are the worst things in football but I know you are strong and you will come back, you deserve the best, my man."
Meanwhile, fellow Arsenal star Ozil tweeted his support to the England international.
"Oh no," he tweeted. "Get well soon Danny."
As Arsenal wait to find out the extent of the injury, Emery said his players were worried about their team-mate after the final whistle following a likely serious injury.
“When one player suffers an injury like that the mind thinks of the player first," he said. "I think the players were concentrated for the match but when we finished the first thing was to ask about him."